The specific dynamic action of southern catfish, <Emphasis Type="Italic">Silurus meridonalis</Emphasis> Chen,fed diets containing either raw or precooked corn starch or glucose

The growth performance of carnivorous southern catfish (Silurus meridionalis) was lower when fed a diet containing glucose as a carbohydrate source than when fed one containing starch. To test whether this decreased growth performance was partly due to higher metabolic costs induced by the fast assimilation of dietary glucose, the postprandial metabolic responses of southern catfish juvenile (36.7 ± 1.9 g) fed diets containing either raw or pre-cooked corn starch and glucose were investigated at 27.5°C. The peak metabolic rate of fish fed a raw corn starch diet was significantly higher than that of fish fed precooked corn starch and glucose diets (P < 0.05). The specific dynamic action (SDA) coefficients (energy expended on SDA as a percentage of energy content of the meal) of fish fed raw or precooked corn starch diets were significantly higher than that of fish fed a glucose diet (P < 0.05). The postprandial metabolic rate of fish fed a raw starch diet displayed a classic response – increased metabolic rate immediately after feeding, followed by a decreased metabolic rate several hours after feeding – as has been documented earlier in this species. However, the postprandial metabolic rate of fish fed a glucose diet had two alternating cycles of increasing and decreasing metabolic rate, which has not been reported previously. This bimodal pattern of the SDA curve was also found in a subsequent experiment in which purified d-glucose (0.1 g dry mass) was packed into sections of grass carp (Ctenopharyngodon idellus) intestine (0.05 g dry mass). The results suggest that the digestibility and absorption speed of the dietary carbohydrate has a significant effect on postprandial metabolic response in juvenile southern catfish. The results of this study may provide useful data in terms of the utilization of dietary carbohydrates by carnivorous fishes.     

天目铁木生长节律的观察

根据1987和1988两年对天目铁木成龄、幼龄树木和苗木生长和发育进程的观测资料,结合两年气象因素的变化,我们报道了此一珍稀树种的年生长发育周期及其与气象因素的关系。观测表明,2月中旬,日均气温2℃以上,芽开始萌动,3月中旬展叶,4月中旬新梢伸长至7月伸长结束,无二次抽梢。雄花序于2月中旬萌动,4月中上旬开放,下旬花谢。6月初形成新的雄花序。雌花序在4月中旬开放,受粉后于6月初出现花被。果实经过大约160～180d生长,于9～10月成熟。种子春播,4月中旬萌发,少数种子可延迟至第2年发芽。在4～5月份气温20℃以下时,幼苗生长缓慢,6月中旬至9月中旬日均气温22～25℃,月降水量200mm左右为苗木生长高峰期。在水肥供应充分时,苗木速生,高径比较大,根系分布较浅,易风倒。造林时宜深栽。     

郴州市城市道路绿地景观现状及其发展研究

受山地城市建设用地条件所限,郴州市城市道路绿地景观建设先天不足。文章分析了郴州市道路绿地景观建设的现状和存在问题,提出了相应的城市道路绿地建设发展方向及对策,以争创国家园林城市。     

樟莹叶甲空间格局及其应用研究

应用多种方法测定了樟莹叶甲卵和幼虫的空间格局，结果表明：樟莹叶甲的卵和幼虫符合Neyman分布，分布的基本成份都是稀疏的个体群，幼虫在林内由聚集分布不断扩散为均匀分布．应用Iwao方法，计算了在不同虫口密度下的林间调查的最适抽样数，分析了幼虫的序贯抽样．     

pH对三七块根花色苷颜色呈现和降解的效应*

 用分光光度法在体外研究了pH对三七块根花色苷呈色和降解的效应,结果表明： 该花色苷在可见光区的吸收光谱和降解速率均具独特的pH依赖性。在pH 2.0,该花色苷呈现最强烈的红色。随着pH从0增加到13.0,该花色苷在可见光区的最大吸收波长（λ _{vis max}）依次出现红移、蓝移,然后消失,在可见光区最大吸收波长处的吸光值（A _{λvis max}）呈现为一条单峰曲线,唯一的峰在pH 2.0处。当原始pH值被恢复到20后,如果原始pH值≤60,花色苷的红色均被恢复得更浓烈,λ _{vis max}不同程度地趋向532nm,_{Aλvis max}增加;如果原始pH值≥7.0,花色苷的红色根本不能被恢复,λ _{vis max}几乎不变,_{Aλvis max}仍然维持低水平。在15℃,黑暗中,该花色苷在pH 0~6.0条件下均随时间而降解,在pH 2.0时的降解速度最慢,当pH ≤ 3.0时,该花色苷在总体上降解缓慢;此外,该花色苷的降解过程几乎符合一级反应动力学。本文可为三七块根颜色呈现的机理探索及其色素的开发、利用提供参考。     

The growth performance of southern catfish fed diets with raw, precooked cornstarch and glucose at two levels

The ability of juvenile carnivorous southern catfish (Silurus meridionalis Chen) to use different levels, kinds and physic state (glucose, raw cornstarch and precooked cornstarch) of dietary carbohydrate was evaluated in term of growth performance. All diets contained 100 g kg^?1 lipid and 16 kJ metabolizable energy. Three isonitrogeneus (400 g kg^?1) diets were formulated to contain 150 g kg^?1 raw cornstarch, precooked cornstarch and glucose. Another three isonitrogeneus (300 g kg^?1) diets were formulated to contain 300 g kg^?1 raw cornstarch, precooked cornstarch and glucose. A control diet was formulated with no carbohydrate containing 500 g kg^?1 protein. Each experimental diet was fed to four tanks of 10 fish (28.3 ± 0.5 g) for 8 weeks at 27.5 °C. Specific growth rate (SGR) of 300 g kg^?1 glucose diet was significantly lower than those of other diets (P < 0.05). Feeding rates (FR) of 300 g kg^?1 glucose and control diets were significantly lower than those of the other diets (P < 0.05). Feed efficiency (FE) was significantly decreased with increased dietary carbohydrate level (P < 0.05). Feed efficiency of the 300 g kg^?1 glucose diet was significantly lower than those of the 300 g kg^?1 raw and precooked cornstarch diets (P < 0.05). The protein efficiency ratio (PER) was significantly increased with dietary carbohydrate level except that of the 300 g kg^?1 glucose diet, which was lowest among all diets (P < 0.05). The results suggested that both dietary starch and glucose were utilized for energy in southern catfish and had a protein‐sparing effect. At 150 g kg^?1 inclusion level, the utilization of raw and precooked cornstarch and glucose did not vary significantly, but a higher dietary glucose level (300 g kg^?1) had a markedly detrimental effect on growth in southern catfish.     

梅友二三事

陈俊愉和赵守边是我国乃至世界著名的梅花专家。为了摸清我国梅花的家底他们历经千辛万苦,为了让梅花开遍祖国的大江南北他们跋山涉水,为了让梅花走向世界服务世界他们付出了毕生的精力。他们为我国和世界梅花事业的发展做出了巨大的贡献。他们二人是生活中的挚友,更是工作中的诤友。     

生长调节剂对柳莓枝插生根的影响

研究了2种植物生长调节剂对柳莓1 a生枝扦插生根的影响。结果表明:柳莓为皮部生根类型,属较易生根植物;分别用255、01、00 mg/kg的3个浓度的IBA和NAA浸泡12 h,并以清水作为对照,均能促进生根,其中以100 mg/kg IBA药剂处理12 h的生根率最高,达到了80%,根系发育指数为19.00。     

诱杀罐及蛆果处理综合防治柑橘大实蝇效果研究

诱杀罐及蛆果处理综合防治柑橘大实蝇效果研究结果表明,大面积防治以塑料袋处理蛆果与挂罐诱杀成虫相结合的措施防治柑桔大实蝇经济有效。     

薄层扫描法对外界诱导降香心材和天然降香心材相似度研究

[目的]比较外界诱导的降香心材与天然降香心材有效化学成分异同。[方法]采用无水乙醚对降香心材粉末进行回流提取,提取液中的化学成分采用薄层色谱法进行分析。[结果]外界诱导形成的降香心材样品中主要化学成分与天然降香心材的基本相同。[结论]外界诱导对降香心材形成有促进作用,为进一步开发利用提供了科学依据。